This invention relates to automated printing machines; and more particularly, to dry offset printing machines. As the demand for wine has increased, so has the demand for natural cork stoppers. To reduce demand for natural cork stoppers, containers other than bottles requiring cork stoppers, such as collapsible bags in boxes and bottles with screw cap lids, have been used. However, the buying public typically perceives collapsible bags stored in boxes with exposed spigots and screw cap bottles as indicators of inferior quality wine. To meet the demand for cork stoppers, synthetic cork stoppers have been developed. These synthetic cork stoppers are made from polymeric materials that have been extruded, or molded during a molding process. These synthetic corks have characteristics similar to their natural counterparts.
In the wine industry, corks are frequently printed with words and other indicia identifying the vineyard where the wine was produced or where the wine is bottled. Printing of natural cork stoppers is typically done using a rotary letter press or rotary letter flex printing system which utilizes a reverse reading hard or soft printing plate which has ink placed on the raised surface. The raised surface of the plate then makes contact with the natural cork, thus transferring the appropriate image. This printing process is typically limited to single color printing.
Printing machines used for printing indicia on natural cork stoppers have been found to be ineffective when used with synthetic cork stoppers. The synthetic stoppers are not as absorbent as natural cork and the printing on such corks, regardless of transfer method, require a forced drying of the printed ink. Additionally, the synthetic corks have a lower coefficient of friction at their surface and require a surface treatment, which oxidizes the surface allowing the printing ink to xe2x80x9cflow outxe2x80x9d when applied to the surface.
Therefore it would be advantageous to have a printing machine capable of imprinting synthetic cork stoppers with forced surface pretreatment and forced ink drying. It would also be advantageous to have a printing machine capable of printing synthetic cork stoppers that more securely holds the synthetic stoppers to reduce the likelihood of machine jams. It would also be advantageous to have a printing machine capable of printing synthetic cork stoppers which is more compact than previously known synthetic cork printing machines.
Therefore, it is an object of the invention to provide a printing machine capable of imprinting synthetic cork stoppers with little smearing.
It is another object of the invention to provide a printing machine capable of printing synthetic cork stoppers that more securely holds the synthetic stoppers to reduce the likelihood of machine jams.
It is another object of the invention to provide a printing machine capable of printing synthetic cork stoppers which is more compact than previously known synthetic cork printing machines.
It is another object of the invention to provide a printing machine which completely processes a synthetic cork in a single, continuous process.
It is another object of the invention to provide a printing machine which imprints synthetic corks which includes both forced surface treatment before printing and forced drying of the cork after printing.
These and other objects of the present invention are achieved in the preferred embodiments disclosed below by providing a rotary printing machine for the printing of synthetic cork stoppers of the type having a surface which is normally non-ink receptive. A Ferris wheel mechanism is provided, having a plurality of evenly spaced carriers mounted a predetermined radial distance from and parallel to the axis of rotation for the Ferris wheel mechanism, each carrier for rotatably holding a synthetic cork stopper. An indexing drive system controls incremental rotation of the Ferris wheel mechanism through a predetermined sequence of steps, and a cork feeder introduces a single synthetic cork stopper into each of the carriers as empty ones of the carriers are presented one-by-one at the cork feeder. A corona discharger treats the surface of each synthetic cork stopper prior to being printed with sufficient energy to alter the surface energy of the cork sufficiently to permit receptivity of printing ink. A rotary printing system rotatably imprints with ink the surface of each held synthetic cork stopper with an image.
According to one preferred embodiment of the invention, a carrier driver is provided for rotating each cork stopper as the surface of the stopper is being treated by the corona discharger.
According to another preferred embodiment of the invention, the Ferris wheel mechanism further comprises a coaxially-mounted drive axle coupled to the indexing drive system, and two parallel, spaced apart circular plates coaxially mounted on the drive axle.
According to yet another preferred embodiment of the invention, each carrier further comprises a stationary holder rotatably mounted on one of the plates, a movable holder rotatably mounted on the other of the plates opposite the stationary holder, the moveable holder being moveable between an open position and an engaged position with respect to the stationary holder such that when in the open position the synthetic cork stopper drops out of the carrier and the Ferris wheel mechanism and when in the engaged position the synthetic cork stopper is held between the moveable and stationary holders; and movement means for moving the moveable holder between the open and engaged positions.
Preferably, the stationary holder and moveable holder have concave surfaces for receiving the ends of the synthetic cork stopper.
According to yet another preferred embodiment of the invention, the stationary holder and moveable holder are removably mounted on their respective plates.
According to yet another preferred embodiment of the invention, the stationary holder and moveable holder each further comprise a removably mounted cup for holding the synthetic cork.
According to yet another preferred embodiment of the invention, a slip clutch is provided for interconnecting the drive axle to the indexing drive system means.
According to yet another preferred embodiment of the invention, the printing machine includes a plurality of carrier spin drivers positioned adjacent the Ferris wheel mechanism at each step where the synthetic cork stopper is being treated, printed and dried, each carrier spin driver having a continuously rotating drive wheel, and a spin pulley coaxially mounted on one of the rotatable holders in each carrier, the spin pulley removably engageable with the drive wheel of a carrier spin driver when the carrier is positioned at a step where the synthetic cork is being treated, printed and dried.
According to yet another preferred embodiment of the invention, the dry offset rotary printing means further comprises a plurality of rotary print heads with each print head providing a different color in an imprinted image.
According to yet another preferred embodiment of the invention, the Ferris wheel mechanism further comprises a coaxial, rotatably mounted drive axle coupled to the indexing drive system means and a circular plate coaxially mounted on the drive axle.
According to yet another preferred embodiment of the invention, each carrier further comprises a stationary holder rotatably mounted on the surface of the plate and a mounting arm mounted on the surface of the plate adjacent each stationary holder. A movable holder is rotatably mounted on the mounting arm opposite the stationary holder, and is moveable between an open position and an engaged position with respect to the stationary holder such that when in the open position the synthetic cork stopper drops out the carrier and the Ferris wheel mechanism and when in the engaged position the synthetic cork stopper is rotatably held between the moveable and stationary holders. Movement means permit movement of the moveable holder between the open and engaged positions.
According to yet another preferred embodiment of the invention, the printing machine further comprises a plurality of carrier spin drivers positioned adjacent the Ferris wheel mechanism at each step where the synthetic cork stopper is being treated, printed and dried, each carrier spin driver having a continuously rotating drive wheel, and a spin pulley coaxially mounted on one of the rotatable holders in each carrier, the spin pulley removably engageable with the drive wheel of a carrier spin driver when the carrier is positioned at a step where the synthetic cork is being treated, printed and dried.
An embodiment of the method for printing indicia on synthetic cork stoppers according to the invention comprises the steps of introducing a single synthetic cork stopper of the type having a normally non-ink receptive surface into a carrier of a Ferris wheel mechanism, treating the synthetic cork stopper surface prior to being printed to render the surface at least temporarily receptive to printing ink, rotatably imprinting an image on the surface of the synthetic cork stopper in the carrier of the Ferris wheel mechanism, drying the ink on freshly imprinted synthetic cork stopper, indexing the rotation of the Ferris wheel mechanism to present the carrier of the Ferris wheel mechanism to stations for treating, imprinting, and drying corks held in the carriers of the Ferris wheel mechanism.
According to one preferred embodiment of the invention, the method includes the step of moving a moveable holder of the carrier with respect to a stationary holder of the carrier between an open position and an engaged position such that the synthetic cork stopper drops out of the carrier in the open position and the synthetic cork stopper is held between the moveable and stationary holders in the engaged position.
According to another preferred embodiment of the invention, the method disengaging a drive axle from an indexing drive system in response to a jam so that the indexing rotation ceases.
In alternative embodiments, the carriers are removably mounted in the Ferris wheel mechanism, the carriers have removable cups used for holding the synthetic corks, and the carriers may be independently rotated at various carrier positions using a carrier spin drive. In other embodiments, the Ferris wheel mechanism comprises a single circular plate mounted on the drive axle with the cork stopper carriers mounted on one side of this plate. Further, a slip clutch mechanism may be provided between the Ferris wheel mechanism and the indexing drive system to reduce the likelihood of damage to the indexing drive should jams occur.
Because each cork is individually held in place during the steps of corona treatment, printing and drying, the down time caused by corks not properly releasing from the print drums is reduced. Further, the Ferris wheel mechanism allows a misfed cork to drop through the mechanism and out of the machine. Lastly, because the carriers and/or their cups are readily removable, the printing machine of the present invention may be quickly retooled for use with a variety of lengths and diameters of synthetic corks.